package q677;

import java.util.TreeMap;

class MapSum {

    private class Node{
        public int value;
        public TreeMap<Character,Node> next;

        public Node(int value) {
            this.value = value;
            next = new TreeMap<>();

        }

        public Node(){
            this(0);
        }
    }

    private Node root;

    /** Initialize your data structure here. */
    public MapSum() {
        root = new Node();
    }
    
    public void insert(String key, int val) {

        Node cur = root;
        for (int i = 0 ; i < key.length() ; i++) {
            char c = key.charAt(i);
            if (cur.next.get(c) == null)
                cur.next.put(c, new Node(0));
            cur = cur.next.get(c);
        }
        cur.value = val;
    }
    
    public int sum(String prefix) {

        Node cur = root;
        for (int i=0 ; i < prefix.length(); i++) {
            char c = prefix.charAt(i);
            if (cur.next.get(c) == null)
                return 0;
            cur = cur.next.get(c);
        }
        //此时，cur指向的就是前缀最后一个字母所对应的节点
        return sum(cur);
    }

    //遍历Node已经Node的所有子树，将所有value的值加起来
    private int sum(Node node) {
        if (node.next.size() == 0)//为叶子节点
            return node.value;

        int res = node.value;

        for (char c:node.next.keySet())
            res += sum(node.next.get(c));
        return res;
    }
}

/**
 * Your MapSum object will be instantiated and called as such:
 * MapSum obj = new MapSum();
 * obj.insert(key,val);
 * int param_2 = obj.sum(prefix);
 */